1. Field of the Invention
Embodiments of the invention relate to a stereoscopic image display device capable of synchronizing left and right eye images displayed on a display device with an operation of a polarization switching element and a method of driving the stereoscopic image display.
2. Discussion of the Related Art
A stereoscopic image display device is mainly classified into a stereoscopic technique and an autostereoscopic technique.
In the stereoscopic technique providing a high stereoscopic effect through a difference between left and right eye images, there are a glasses type and a non-glasses type. Both the two types have been put to practical use. In the glasses type stereoscopic image display device, left and right eye images whose polarization directions change are displayed on a direct type display device or a projector or the left and right eye images are time-division displayed on the direct type display device or the projector. The glasses type stereoscopic image display device displays a stereoscopic image using polarization glasses or a liquid crystal shutter. In the non-glasses type stereoscopic image display device, an optical plate, such as a parallax barrier, for separating optical axes of left and right eye images from each other is positioned in the front or in the rear of a display screen.
The glasses type stereoscopic image display device may include a switching retarder for switching polarization characteristic of light incident on polarization glasses on a display device. In the glasses type stereoscopic image display device, the display device alternately displays the left and right eye images, and the switching retarder switches the polarization characteristic of light incident on the polarization glasses. Accordingly, the glasses type stereoscopic image display device can display a stereoscopic image without a reduction in resolution by time-division displaying the left and right eye images.
A liquid crystal display (LCD) may be used as the display device of the stereoscopic image display device. The liquid crystal display sequentially writes data from a first line to a last line of the display device to thereby display an image. When the liquid crystal display starts to be charged to the data, liquid crystal molecules of the liquid crystal display react and start to move. Because of such a delay of a response time, a display time of an entire image during 1 frame period ranges from a response end time point of liquid crystals after writing data to all of liquid crystal cells of the liquid crystal display to a time point immediately before writing data to a first line in a next frame period. When the liquid crystal display alternately displays the left and right eye images, the related art glasses type stereoscopic image display device may cause pseudo-stereoscopic vision in a boundary potion where the left eye image changes to the right eye image or in a boundary potion where the right eye image changes to the left eye image because the data writing of the liquid crystal display is not synchronized with an operation of the switching retarder.
Accordingly, in the glasses type stereoscopic image display device, the left and right eye images have to be alternately displayed on the display device, and the switching retarder has to be synchronized with the left and right eye images. However, the left and right eye images may be displayed on the display device in the unstable order or the order of the left and right eye images may change if an initial drive of the display device is unstable or driving circuits of the display device may be operated in erroneous operation. As a result, the left and right eye images displayed on the display device is not synchronized with the operation of the switching retarder because of the unstable order of the left and right eye images, and thus the pseudo-stereoscopic vision may be caused.